The present invention relates to wireless communication and, more particularly, to a Binary Amplitude Shift Key (BASK) demodulator and a method for demodulating and decoding a BASK modulated signal.
Backscatter used in conjunction with BASK modulation is a simple and cost effective approach for communicating data across relatively short distances. This approach relies on inductive coupling of primary and secondary coils in which current/voltage in the secondary coil is BASK modulated. The modulated current/voltage affects the loading on the primary coil and therefore a BASK modulated signal is generated across the primary coil.
Demodulation of BASK modulated signals typically is performed by envelope detection. Although envelope detection is a simple and relatively inexpensive demodulation technique, it generally is only suitable for BASK modulated signals that have known limited range or expected logic 1 and logic 0 levels. Hence, for instance, when considering backscatter in conjunction with BASK modulation, the amplitude of the driving voltage or frequency may be adjusted to vary the power supplied to the primary coil. Consequently, the resulting maximum Amplitude Shift Keying (ASK) modulated signal values for logic 1 and 0 may vary considerably and thus may not be readily distinguishable by conventional envelope detection.
In addition to the above, information or signals transmitted by backscatter may be susceptible to glitches caused by electromagnetic interference. It therefore would be useful if the effects of such glitches are alleviated or at least reduced.